Plaster board and method of making same



Patented Oct. 7, 1924.

UNITED sTATEs PATENT oFricE.

l GEORGE H. ELLIS, 0F ST. PAUL, MINNESOTA.

PLASTER BOARD AND METHOD 0F MAKING SAME.

Application led April 2,

To all whom z't may cof/wem:

Be it known that I, GEORGE H. ELLIS, a citizen of the United States, residin at St. Paul, in the county of Ramsey and tate of Minnesota, have invented certain new and useful Improvements in Plasterl Board and Methods of Making Same; and I do hereby declare the followin to be a full, clear, and exact description vo the invention, such as will enable others skilled in the art to which 'it appertains to make and use the same. v

This invention relatesto a plaster .board and method of making the same. Such boards are now widely used commercially for holding plaster or stucco, both in in- `terior and exterior building construction.

The board of the present invention is made of` compressed fibrous material and comprises a Hat body having plaster holding projections thereon. In the prior art, the body of the board has been formed with depressions of various kinds in which the plaster was supposed to enter so as to be held in position or locked in place.

It is an object of the present invention to provide a board comprising a flat body which has spaced members of comparatively small area projecting therefrom instead of having depressions formed therein.

It is a further object of the invention to provide such a board in which the projections are regularly formed and regularly spaced and are further lslightly upset at their outer ends to form a holding means for the plaster.

It is still another object of the invention to provide a method of making such a board whereby the body of the board between the projections will be compressed a greater degree than the body of the board under the projections.

These and other objects and advantages of the invention will be apparent from the following description made in connection with the accom anying drawings in which- Fig. 1 is a p an view of one form of apparatus used in the process;

Fig. 2 is a central vertical section of Fig. l;

Fig. 3 is alfragmentary section showing one step of the process;

Fig. 4 is a fragmentary top plan view of the boardat an intermediate point in the process;

F 5 is a vertical section taken on the vit has been found in practice that -cost in practically all countries 1923. Serial No. 629,402.

line 5-5 of Fig. 4, Figs. 3, 4 and 5 'being shown on an enlarged scale;

F ig. 6 is a top plan view of the finished boar Fig. 7 is a top plan view showing one of the uses of the board having a portion thereof broken away; and

Fig. 8 is a vertical section taken on the line 8-48 of Fig. 7 shown on anenlarged scale.

The improved insulated lathboard may be commercially made at llow cost from various different fibers, such, for example, as Ycereal straws disintegrated and pulped and preferably reduced approximately to what is known as half stock. However, the board may, in point of cheapness of manufacture and efficiency of product, be made from pulped waste paper, which paper may be easlly obtained in large quantities at lou7 and especially in the'United States.

In using the waste and better grades and reused to make a high grade paper, while the colored paper may be sorted out and the die stock reclaimed therefrom. By this practice, the salvage obtained in handling the paper will pay for the cost of the same, so that the portion of paper used in makin the lathboard costs practically nothing. aste paper `also contains sizing which, to a considerablev degree,'renders the board madeV therefrom waterproof. The waste paper is pulped, but need not be, and preferably is not entirely disintegrated. It is, however, reduced to a pulp of such character that it may be molded or pressed to the desired form.

In constructing thexboard by the present method the same is formed with spaced projections on one surface thereof between which the plaster is adapted to be placed to be held in position thereby. These projections, as shown in Figs. 3 and 6, constitute button-like members extending from one face of the board and have their top or paper, the sulphite of paper can be sorted outer surface or portions slightly upset,

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Figs. 1 and 2. This apparatus comprises a box-shaped mold 1 illustrated as of rectangular form having in its bottom a plurality of spaced apertures or passages. Members 2 are adapted to fit and slide 1n said passages, which members may be of any desired shape in cross section but which are illustrated as being circular in cross section. rlhe members 2 are provided with convex perforated surfaces facing into the box l and said members are also carried by a plate or crosshead 3 slidably mounted on guide members 4 secured to the box 1 and which are illustrated as being in the form of headed bolts, the heads of whichlimit the movement of the crosshead 3. When the crosshead is in its outermost position, the perforated convex surfaces 5 of the membersv 2 are disposed in the passages in the box 1 at some distance below the bottom of the box. With the members 2 in this position a layer of semi-uid fibrous material from whiclr the board is made is placed in the mold and a frame 6 which fits the moldis placed thereon, which frame comprises for practically its entire extent of surface, a screen 7. The material is then compressed by pressure exerted between the frame 6 and the bottom of the mold. The water in the material can readily escape through the screen 7 and through the perforated surfaces 5. Owing to the fact that the material is only partly fluid and also due to the fibrous nature thereof, the material between the frame 6 and the imperforate bottom of the mold does not flow outwardly so that the material is evenly distributed, but such portion of the material is compacted to a greater extent than the portion of the material which lies between the frame 6 and the perforated surfaces 5. After lthe material has been sufiiciently compressed, the frame 1 is swung about a shaft 8 carried by the frame 9, which shaft and frame support the mold box 1 to the position indicated in dotted lines in Fig. 2. The frame 1 is provided with a pair of arms 10 carrying lugs'at their outer ends through which passes the shaft 8. When the mold is in the position shown in full lines in Fig. 2 it is supported upon an upright wall 1l of the frame 9 and when it is swung to the position shown in dotted lines it is supported upon the lower wall 12. `When the mold is in the position indicated by dotted lines, the cross head 3 can be pressed downwardly sliding on the guide rods 4 and the layer of material formin the board will be pressed out of the mo d. The form of the board as it is thus taken from the mold is clearly shown in Figs. 4 and 5, one surface of the board has formed thereon a plurality of projecting cylindrical members having concave outer surfaces. rlhe perforations in the surfaces 5 of the members 2 anonce also cause small knobs or projections on the concave outer surface of the projections 13 on the board. With the board in this condition, thc same is placed upon a suitable table or platform 14 and passed unler a roller 15 illustrated as being carried on a central shaft 16.A The roller acting on the top of the projections 13 flattens out the concave surface and upsets the outer end of the projection so that the sides of the members 13 are undercut or said members, in other words, are somewhat T-shaped. The plasterboard is now dried and then ready for use.

It is thought the use of the board will be obvious from the previous description. rlFhe sections of the boarl will be nailed to the studding or surface of the building to be plastered and the plaster, stucco or similar material will be plastered onto the board between and over the projections 13. With plaster it will only be necessary to cover the surface of the members 13 with a very thin layer of plaster, the main layer of plaster extending between said projections. The use of the board, therefore, effects quite a saving in the volume of plaster used over boards in which the plaster was held in depressions in the surface thereof. Owing to the upset ends of the members 13 the plaster will be interlocked under said ends and thus positively locked and held in position. Considerable difficulty has been experienced With stucco plaster which is commonly used on the exteriors of buildings in getting the stucco into sufficiently close contact with the supporting material. Such stucco is commonl placed on metal lath of various forms. xperiments and investigations on actual pieces of work have shown that only a comparatively small area of the metal lath is efliciently contacted by the stucco. The indentations or` spaces formed in metal lath must be sufficiently small to hold the stucco and said lath must also constitute the reinforcing means for the stucco. With applicants device, a screen of large mesh can be laid over the tops of the members 13 and secured thereto, as shown in Figs. 7 and 8, and will form the reinforcing means for the layer of stucco.- The said screen will be held in proper position relative to the said layer by the members 13 and owing to the larger mesh of the screen there will be no difiiculty in etting the stucco into the meshes thereof. rlhe stucco will be locked in position by the' members 13 between which it will readil enter. A very compact and efiicient rein orced layer of stucco is thus formed with the reinforcing medium in the correct position.

The board made, as above described, is not only a very good insulator but is quite strong and tough, owing to the fibrous material therein.

After the board has been properly dried the surface containing the projections 13, as well as said projections, may, if desired, be coated or impregnated with any suitable water-proofing material, such as coal tar, varnish, silicates of soda or any other of the known water proofing or flre proofing substances.

From the above description it is seen that applicant has provided a lathboard of great simplicity of eiiciency as well as a novel method of producing the same. The body of the board between the projections is quite compact, while the `projections themselves have very compact outer portions to form an eilicient 4holding means for the plaster. The high insulating qualities of the board render the same capable of being used both as a sheathing and as a lathing so that the board can be used on the exterior of a building without the wooden or other sheathmg usually employed.

It will, of course, be understood, that various changes may be made in the form,

composition, details and arrangement of the f board structure and in the various steps of the process without departing from the scope of applicants invention, which, generally stated, consists in a method and product capable of carrying out the objects enumerated and such as shownI and described and eet forth in the appended claims.

What is claimed is:

1. A plaster board comprising a fiat integral body formed throughout of fibrous material having spaced projections extending from one surface thereof, said projectionsbeing spaced from each other in all directions. l

2. A plaster board comprising an in al flat body of fibrous material having projecting from one surface thereofregularly spaced button-like members having upset and compressed outer ends.

3. A plaster board formed in one flat integral body of similar fibrous material having spaced upset projections extending from one surface thereof, the portion of the board betweenthe projections being pressed to a greater degree than the portion in and under thev projections.

4. The method of making a plaster board which comprises compressing a layer of semiiuid fibrous material between a rforated and a partially perforated surice to allow the moisture to escape therefrom, and further compressing the portion contacted by the nonerforated surface to form spaced cylindrical) portion whereby the portion pressed by the non-perforated surface is of greater density.

5. The method of making a plaster board which comprises compressing a layer of semi-fluid substantially homogeneous fibrous material to express the moisture therefrom, compressing a certain area thereof to a greater extent to form spaced cylindrical projections surrounded by said area, forming the ends of said projections with concave outer surfaces, and then compressing projections within saidI the tops of said projections to upset the p ends thereof into mushroom shape. In testimony whereof I affix my si GEORGE H. E

ature. 

